A shady strategy for photosynthesis.A shady strategy for photosynthesis"When faced with an adverse environment, animals in general have the option of moving away from it; plants cannot do that," notes plant biologist Anastasios Melis of the University of California, Berkeley The University of California, Berkeley is a public research university located in Berkeley, California, United States. Commonly referred to as UC Berkeley, Berkeley and Cal . Yet plants have a molecular tactic that may be just as effective, he says. In the October PROCEEDING OF THE NATIONAL ACADEMY OF SCIENCES (Vol. 87, No. 19), Melis and his colleagues report that an adaptive mechanism inside plant cells appears to sense the changing menu of light wavelengths and tune the light-hungry photosynthesis system to make best use of the available wavelength blend, which arrives in sunlight filtered through water, trees, overlying overlying suffocation of piglets by the sow. The piglets may be weak from illness or malnutrition, the sow may be clumsy or ill, the pen may be inadequate in size or poorly designed so that piglets cannot escape. plants or other obstacles. Plants feature molecular complexes called photosystem Photosystems (ancient Greek: phos = light and systema = assembly) are protein complexes involved in photosynthesis. They are found in the thylakoid membranes of plants, algae and cyanobacteria (in plants and algae these are located in the chloroplasts), or in the I and photosystem II, which reside in stacks of membranes within cell organelles called chloroplasts. Each photosystem has a certain blend of chlorophylls and other pigments that absorb specific wavelengths of photosynthesis-driving light. Melis, working with Wah Soon Chow and Jan M. Anderson of the Commonwealth Scientific and Industrial Organisation in Canberra, Australia, observed that the relative amounts of photosystems I and II in pea plants change in response to incoming light whose wavelengths match the absorbance absorbance /ab·sor·bance/ (-sor´bans) 1. in analytical chemistry, a measure of the light that a solution does not transmit compared to a pure solution. Symbol . 2. of one or the other photosystem. This enables pea plants and other higher plants, as well as photosynthetic bacteria and algae algae (ăl`jē) [plural of Lat. alga=seaweed], a large and diverse group of primarily aquatic plantlike organisms. These organisms were previously classified as a primitive subkingdom of the plant kingdom, the thallophytes (plants that , to maintain nearly optimum photosynthetic efficiency as incoming wavelengths change over periods as brief as a few days, Melis says. The researchers cite previous studies by others showing that many species maintain striking photosynthetic efficiency despite "diverse light habitats." They also cite their own earlier work, which indicated that the relative amounts of photosystems I and II in plants change in response to different light conditions during growth. The new work shows that these molecular changes permit plants to retain photosynthetic efficiency "near the theoretical maximum," they say. No so fast, warns John Whitmarsh of the U.S. Department of Agriculture and the University of Illinois University of Illinois may refer to:
v. o·ver·sim·pli·fied, o·ver·sim·pli·fy·ing, o·ver·sim·pli·fies v.tr. To simplify to the point of causing misrepresentation, misconception, or error. v.intr. " and argues that experimental uncertainties could account for the changes in photosystem ratio and photosynthetic efficiency measured by Melis' group. |
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